How to create an array with random values with the help of JavaScript ?

The task is to generate an array with random values with the help of JavaScript. There are two approaches which are discussed below: 

Approach 1:

• Use Math.random() and Math.floor() methods to get the random values.
• Push the values one by one in the array (But this approach may generate repeated values).

Example: This example implements the above approach. 

Javascript

function gfg_Run() {
    console.log(Array.from({
        length: 10
    }, () => Math.floor(Math.random() * 10)));
}
gfg_Run()

Output

[
  8, 6, 4, 3, 9,
  2, 8, 9, 7, 8
]

Approach 2:

• Create an array and put the values in it (like 1 at index 0, 2 at index 1, and 3 at index 2 in the same order by a loop.)
• Assign a variable (tp) = length of the array.
• Run a loop on variable(tp).
• Inside the loop use Math.random() and Math.floor() methods to get the random index of the array.
• Swap this array value with the index(tp) and decrease the variable(tp) by 1.
• Run the loop until variable(tp) becomes 0.

Example: This example implements the above approach. 

Javascript

let a = []
for ( i = 0; i < 10; ++i) a[i] = i;

// Array like[1, 2, 3, 4, ...]

function createRandom(arr) {
    let tmp, cur, tp = arr.length;
    if (tp)

        // Run until tp becomes 0.
        while (--tp) {

            // Generating the random index.
            cur = Math.floor(Math.random() * (tp + 1));

            // Getting the index(cur) value in variable(tmp).
            tmp = arr[cur];

            // Moving the index(tp) value to index(cur).
            arr[cur] = arr[tp];

            // Moving back the tmp value to
            // index(tp), Swapping is done.
            arr[tp] = tmp;
        }
    return arr;
}

function gfg_Run() {
    console.log(createRandom(a));
}
gfg_Run()

Output

[
  0, 9, 4, 3, 6,
  8, 2, 7, 1, 5
]